Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
[wrt350n-kernel.git] / arch / parisc / kernel / smp.c
blob85fc7754ec255a36624b038031fb4103bcc76d3c
1 /*
2 ** SMP Support
3 **
4 ** Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
5 ** Copyright (C) 1999 David Mosberger-Tang <davidm@hpl.hp.com>
6 ** Copyright (C) 2001,2004 Grant Grundler <grundler@parisc-linux.org>
7 **
8 ** Lots of stuff stolen from arch/alpha/kernel/smp.c
9 ** ...and then parisc stole from arch/ia64/kernel/smp.c. Thanks David! :^)
11 ** Thanks to John Curry and Ullas Ponnadi. I learned a lot from their work.
12 ** -grant (1/12/2001)
14 ** This program is free software; you can redistribute it and/or modify
15 ** it under the terms of the GNU General Public License as published by
16 ** the Free Software Foundation; either version 2 of the License, or
17 ** (at your option) any later version.
19 #include <linux/types.h>
20 #include <linux/spinlock.h>
21 #include <linux/slab.h>
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/sched.h>
26 #include <linux/init.h>
27 #include <linux/interrupt.h>
28 #include <linux/smp.h>
29 #include <linux/kernel_stat.h>
30 #include <linux/mm.h>
31 #include <linux/err.h>
32 #include <linux/delay.h>
33 #include <linux/bitops.h>
35 #include <asm/system.h>
36 #include <asm/atomic.h>
37 #include <asm/current.h>
38 #include <asm/delay.h>
39 #include <asm/tlbflush.h>
41 #include <asm/io.h>
42 #include <asm/irq.h> /* for CPU_IRQ_REGION and friends */
43 #include <asm/mmu_context.h>
44 #include <asm/page.h>
45 #include <asm/pgtable.h>
46 #include <asm/pgalloc.h>
47 #include <asm/processor.h>
48 #include <asm/ptrace.h>
49 #include <asm/unistd.h>
50 #include <asm/cacheflush.h>
52 #undef DEBUG_SMP
53 #ifdef DEBUG_SMP
54 static int smp_debug_lvl = 0;
55 #define smp_debug(lvl, printargs...) \
56 if (lvl >= smp_debug_lvl) \
57 printk(printargs);
58 #else
59 #define smp_debug(lvl, ...)
60 #endif /* DEBUG_SMP */
62 DEFINE_SPINLOCK(smp_lock);
64 volatile struct task_struct *smp_init_current_idle_task;
66 static volatile int cpu_now_booting __read_mostly = 0; /* track which CPU is booting */
68 static int parisc_max_cpus __read_mostly = 1;
70 /* online cpus are ones that we've managed to bring up completely
71 * possible cpus are all valid cpu
72 * present cpus are all detected cpu
74 * On startup we bring up the "possible" cpus. Since we discover
75 * CPUs later, we add them as hotplug, so the possible cpu mask is
76 * empty in the beginning.
79 cpumask_t cpu_online_map __read_mostly = CPU_MASK_NONE; /* Bitmap of online CPUs */
80 cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL; /* Bitmap of Present CPUs */
82 EXPORT_SYMBOL(cpu_online_map);
83 EXPORT_SYMBOL(cpu_possible_map);
85 DEFINE_PER_CPU(spinlock_t, ipi_lock) = SPIN_LOCK_UNLOCKED;
87 struct smp_call_struct {
88 void (*func) (void *info);
89 void *info;
90 long wait;
91 atomic_t unstarted_count;
92 atomic_t unfinished_count;
94 static volatile struct smp_call_struct *smp_call_function_data;
96 enum ipi_message_type {
97 IPI_NOP=0,
98 IPI_RESCHEDULE=1,
99 IPI_CALL_FUNC,
100 IPI_CPU_START,
101 IPI_CPU_STOP,
102 IPI_CPU_TEST
106 /********** SMP inter processor interrupt and communication routines */
108 #undef PER_CPU_IRQ_REGION
109 #ifdef PER_CPU_IRQ_REGION
110 /* XXX REVISIT Ignore for now.
111 ** *May* need this "hook" to register IPI handler
112 ** once we have perCPU ExtIntr switch tables.
114 static void
115 ipi_init(int cpuid)
117 #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region
119 if(cpu_online(cpuid) )
121 switch_to_idle_task(current);
124 return;
126 #endif
130 ** Yoink this CPU from the runnable list...
133 static void
134 halt_processor(void)
136 /* REVISIT : redirect I/O Interrupts to another CPU? */
137 /* REVISIT : does PM *know* this CPU isn't available? */
138 cpu_clear(smp_processor_id(), cpu_online_map);
139 local_irq_disable();
140 for (;;)
145 irqreturn_t
146 ipi_interrupt(int irq, void *dev_id)
148 int this_cpu = smp_processor_id();
149 struct cpuinfo_parisc *p = &cpu_data[this_cpu];
150 unsigned long ops;
151 unsigned long flags;
153 /* Count this now; we may make a call that never returns. */
154 p->ipi_count++;
156 mb(); /* Order interrupt and bit testing. */
158 for (;;) {
159 spinlock_t *lock = &per_cpu(ipi_lock, this_cpu);
160 spin_lock_irqsave(lock, flags);
161 ops = p->pending_ipi;
162 p->pending_ipi = 0;
163 spin_unlock_irqrestore(lock, flags);
165 mb(); /* Order bit clearing and data access. */
167 if (!ops)
168 break;
170 while (ops) {
171 unsigned long which = ffz(~ops);
173 ops &= ~(1 << which);
175 switch (which) {
176 case IPI_NOP:
177 smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu);
178 break;
180 case IPI_RESCHEDULE:
181 smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu);
183 * Reschedule callback. Everything to be
184 * done is done by the interrupt return path.
186 break;
188 case IPI_CALL_FUNC:
189 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu);
191 volatile struct smp_call_struct *data;
192 void (*func)(void *info);
193 void *info;
194 int wait;
196 data = smp_call_function_data;
197 func = data->func;
198 info = data->info;
199 wait = data->wait;
201 mb();
202 atomic_dec ((atomic_t *)&data->unstarted_count);
204 /* At this point, *data can't
205 * be relied upon.
208 (*func)(info);
210 /* Notify the sending CPU that the
211 * task is done.
213 mb();
214 if (wait)
215 atomic_dec ((atomic_t *)&data->unfinished_count);
217 break;
219 case IPI_CPU_START:
220 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu);
221 break;
223 case IPI_CPU_STOP:
224 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu);
225 halt_processor();
226 break;
228 case IPI_CPU_TEST:
229 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu);
230 break;
232 default:
233 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
234 this_cpu, which);
235 return IRQ_NONE;
236 } /* Switch */
237 /* let in any pending interrupts */
238 local_irq_enable();
239 local_irq_disable();
240 } /* while (ops) */
242 return IRQ_HANDLED;
246 static inline void
247 ipi_send(int cpu, enum ipi_message_type op)
249 struct cpuinfo_parisc *p = &cpu_data[cpu];
250 spinlock_t *lock = &per_cpu(ipi_lock, cpu);
251 unsigned long flags;
253 spin_lock_irqsave(lock, flags);
254 p->pending_ipi |= 1 << op;
255 gsc_writel(IPI_IRQ - CPU_IRQ_BASE, cpu_data[cpu].hpa);
256 spin_unlock_irqrestore(lock, flags);
260 static inline void
261 send_IPI_single(int dest_cpu, enum ipi_message_type op)
263 if (dest_cpu == NO_PROC_ID) {
264 BUG();
265 return;
268 ipi_send(dest_cpu, op);
271 static inline void
272 send_IPI_allbutself(enum ipi_message_type op)
274 int i;
276 for_each_online_cpu(i) {
277 if (i != smp_processor_id())
278 send_IPI_single(i, op);
283 inline void
284 smp_send_stop(void) { send_IPI_allbutself(IPI_CPU_STOP); }
286 static inline void
287 smp_send_start(void) { send_IPI_allbutself(IPI_CPU_START); }
289 void
290 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
292 void
293 smp_send_all_nop(void)
295 send_IPI_allbutself(IPI_NOP);
300 * Run a function on all other CPUs.
301 * <func> The function to run. This must be fast and non-blocking.
302 * <info> An arbitrary pointer to pass to the function.
303 * <retry> If true, keep retrying until ready.
304 * <wait> If true, wait until function has completed on other CPUs.
305 * [RETURNS] 0 on success, else a negative status code.
307 * Does not return until remote CPUs are nearly ready to execute <func>
308 * or have executed.
312 smp_call_function (void (*func) (void *info), void *info, int retry, int wait)
314 struct smp_call_struct data;
315 unsigned long timeout;
316 static DEFINE_SPINLOCK(lock);
317 int retries = 0;
319 if (num_online_cpus() < 2)
320 return 0;
322 /* Can deadlock when called with interrupts disabled */
323 WARN_ON(irqs_disabled());
325 /* can also deadlock if IPIs are disabled */
326 WARN_ON((get_eiem() & (1UL<<(CPU_IRQ_MAX - IPI_IRQ))) == 0);
329 data.func = func;
330 data.info = info;
331 data.wait = wait;
332 atomic_set(&data.unstarted_count, num_online_cpus() - 1);
333 atomic_set(&data.unfinished_count, num_online_cpus() - 1);
335 if (retry) {
336 spin_lock (&lock);
337 while (smp_call_function_data != 0)
338 barrier();
340 else {
341 spin_lock (&lock);
342 if (smp_call_function_data) {
343 spin_unlock (&lock);
344 return -EBUSY;
348 smp_call_function_data = &data;
349 spin_unlock (&lock);
351 /* Send a message to all other CPUs and wait for them to respond */
352 send_IPI_allbutself(IPI_CALL_FUNC);
354 retry:
355 /* Wait for response */
356 timeout = jiffies + HZ;
357 while ( (atomic_read (&data.unstarted_count) > 0) &&
358 time_before (jiffies, timeout) )
359 barrier ();
361 if (atomic_read (&data.unstarted_count) > 0) {
362 printk(KERN_CRIT "SMP CALL FUNCTION TIMED OUT! (cpu=%d), try %d\n",
363 smp_processor_id(), ++retries);
364 goto retry;
366 /* We either got one or timed out. Release the lock */
368 mb();
369 smp_call_function_data = NULL;
371 while (wait && atomic_read (&data.unfinished_count) > 0)
372 barrier ();
374 return 0;
377 EXPORT_SYMBOL(smp_call_function);
380 * Flush all other CPU's tlb and then mine. Do this with on_each_cpu()
381 * as we want to ensure all TLB's flushed before proceeding.
384 void
385 smp_flush_tlb_all(void)
387 on_each_cpu(flush_tlb_all_local, NULL, 1, 1);
391 * Called by secondaries to update state and initialize CPU registers.
393 static void __init
394 smp_cpu_init(int cpunum)
396 extern int init_per_cpu(int); /* arch/parisc/kernel/processor.c */
397 extern void init_IRQ(void); /* arch/parisc/kernel/irq.c */
398 extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */
400 /* Set modes and Enable floating point coprocessor */
401 (void) init_per_cpu(cpunum);
403 disable_sr_hashing();
405 mb();
407 /* Well, support 2.4 linux scheme as well. */
408 if (cpu_test_and_set(cpunum, cpu_online_map))
410 extern void machine_halt(void); /* arch/parisc.../process.c */
412 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
413 machine_halt();
416 /* Initialise the idle task for this CPU */
417 atomic_inc(&init_mm.mm_count);
418 current->active_mm = &init_mm;
419 if(current->mm)
420 BUG();
421 enter_lazy_tlb(&init_mm, current);
423 init_IRQ(); /* make sure no IRQs are enabled or pending */
424 start_cpu_itimer();
429 * Slaves start using C here. Indirectly called from smp_slave_stext.
430 * Do what start_kernel() and main() do for boot strap processor (aka monarch)
432 void __init smp_callin(void)
434 int slave_id = cpu_now_booting;
436 smp_cpu_init(slave_id);
437 preempt_disable();
439 flush_cache_all_local(); /* start with known state */
440 flush_tlb_all_local(NULL);
442 local_irq_enable(); /* Interrupts have been off until now */
444 cpu_idle(); /* Wait for timer to schedule some work */
446 /* NOTREACHED */
447 panic("smp_callin() AAAAaaaaahhhh....\n");
451 * Bring one cpu online.
453 int __cpuinit smp_boot_one_cpu(int cpuid)
455 struct task_struct *idle;
456 long timeout;
459 * Create an idle task for this CPU. Note the address wed* give
460 * to kernel_thread is irrelevant -- it's going to start
461 * where OS_BOOT_RENDEVZ vector in SAL says to start. But
462 * this gets all the other task-y sort of data structures set
463 * up like we wish. We need to pull the just created idle task
464 * off the run queue and stuff it into the init_tasks[] array.
465 * Sheesh . . .
468 idle = fork_idle(cpuid);
469 if (IS_ERR(idle))
470 panic("SMP: fork failed for CPU:%d", cpuid);
472 task_thread_info(idle)->cpu = cpuid;
474 /* Let _start know what logical CPU we're booting
475 ** (offset into init_tasks[],cpu_data[])
477 cpu_now_booting = cpuid;
480 ** boot strap code needs to know the task address since
481 ** it also contains the process stack.
483 smp_init_current_idle_task = idle ;
484 mb();
486 printk("Releasing cpu %d now, hpa=%lx\n", cpuid, cpu_data[cpuid].hpa);
489 ** This gets PDC to release the CPU from a very tight loop.
491 ** From the PA-RISC 2.0 Firmware Architecture Reference Specification:
492 ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which
493 ** is executed after receiving the rendezvous signal (an interrupt to
494 ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the
495 ** contents of memory are valid."
497 gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, cpu_data[cpuid].hpa);
498 mb();
501 * OK, wait a bit for that CPU to finish staggering about.
502 * Slave will set a bit when it reaches smp_cpu_init().
503 * Once the "monarch CPU" sees the bit change, it can move on.
505 for (timeout = 0; timeout < 10000; timeout++) {
506 if(cpu_online(cpuid)) {
507 /* Which implies Slave has started up */
508 cpu_now_booting = 0;
509 smp_init_current_idle_task = NULL;
510 goto alive ;
512 udelay(100);
513 barrier();
516 put_task_struct(idle);
517 idle = NULL;
519 printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
520 return -1;
522 alive:
523 /* Remember the Slave data */
524 smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n",
525 cpuid, timeout * 100);
526 return 0;
529 void __devinit smp_prepare_boot_cpu(void)
531 int bootstrap_processor=cpu_data[0].cpuid; /* CPU ID of BSP */
533 /* Setup BSP mappings */
534 printk("SMP: bootstrap CPU ID is %d\n",bootstrap_processor);
536 cpu_set(bootstrap_processor, cpu_online_map);
537 cpu_set(bootstrap_processor, cpu_present_map);
543 ** inventory.c:do_inventory() hasn't yet been run and thus we
544 ** don't 'discover' the additional CPUs until later.
546 void __init smp_prepare_cpus(unsigned int max_cpus)
548 cpus_clear(cpu_present_map);
549 cpu_set(0, cpu_present_map);
551 parisc_max_cpus = max_cpus;
552 if (!max_cpus)
553 printk(KERN_INFO "SMP mode deactivated.\n");
557 void smp_cpus_done(unsigned int cpu_max)
559 return;
563 int __cpuinit __cpu_up(unsigned int cpu)
565 if (cpu != 0 && cpu < parisc_max_cpus)
566 smp_boot_one_cpu(cpu);
568 return cpu_online(cpu) ? 0 : -ENOSYS;
571 #ifdef CONFIG_PROC_FS
572 int __init
573 setup_profiling_timer(unsigned int multiplier)
575 return -EINVAL;
577 #endif